Are identical twins a high risk pregnancy?

Having twins comes with risks and complications not present in singleton pregnancies. Identical twins, also known as monozygotic twins, face additional risks due to sharing the same placenta and amniotic sac. Understanding the risks and how to manage them is key for expectant mothers carrying multiples.

What are the risks of having identical twins?

Some of the main risks associated specifically with identical twins include:

  • Twin-to-twin transfusion syndrome (TTTS) – This happens when blood moves unevenly between the twins via connected blood vessels in the shared placenta, depriving one twin of nutrients and potentially causing heart failure.
  • Selective intrauterine growth restriction (sIUGR) – One baby receives less nutrition than the other, resulting in asymmetric growth.
  • Twin reversed arterial perfusion (TRAP) sequence – A rare abnormality where one twin receives blood flow from the other twin, but does not fully develop.
  • Congenital anomalies – Identical twins have higher rates of congenital disabilities affecting the gastrointestinal system, heart, and brain.
  • Preterm birth – Over 50% of twin pregnancies deliver prematurely, before 37 weeks.
  • Low birth weight – On average, twins weigh around 5.5 pounds each, compared to 7.5 for singletons.
  • Placental problems – Issues with the shared placenta like placenta previa, placental abruption, or vasa previa.
  • Preeclampsia – Mothers pregnant with multiples have 3-4 times higher risk of developing dangerously high blood pressure.
  • Gestational diabetes – Carrying more than one baby increases risk of gestational diabetes.
  • Postpartum hemorrhage – The enlarged uterus and extra placental site creates higher risk of excessive bleeding after delivery.

Additionally, there are general risks associated with any twin pregnancy regardless of zygosity including greater likelihood of needing a C-section, longer hospital stay after birth, and higher infant mortality rates.

How are identical twin pregnancies monitored?

Doctors take additional precautions when monitoring identical twin pregnancies due to the elevated risks.

  • More frequent prenatal visits to track fetal development and check for TTTS signs.
  • Regular ultrasound scans to evaluate fetal growth, amniotic fluid levels, placental health, and screen for anomalies.
  • Nonstress tests starting around week 28 to monitor twin heart rates.
  • Biophysical profiles in the third trimester to check fetal movement, breathing, tone, and amniotic fluid.
  • Monitoring mother for preeclampsia symptoms like high blood pressure.
  • Checking for cervical shortening premature labor.
  • Consulting with maternal-fetal medicine specialist for high-risk management.
  • Testing for gestational diabetes.
  • Increased vigilance for any bleeding, cramping, or decreased fetal movement.

Doctors may recommend admitting the mother to hospital weeks before the due date for closer monitoring if complications develop or early delivery seems likely.

What treatments exist for identical twin complications?

Some specific treatments for identical twin complications include:

  • TTTS – Laser ablation surgery to seal off connecting blood vessels on the placenta.
  • sIUGR – Steroid injections, early delivery, or nutrition supplement to underdeveloped twin.
  • TRAP sequence – Laser or ultrasound guided surgery to disconnect blood flow to non-developing twin.
  • Preeclampsia – Delivering babies early, magnesium sulfate, medication for hypertension.
  • Placental issues – Depending on severity, steroids, early delivery, bed rest, close monitoring.

The best course of treatment depends on the specifics of each case and how far along the pregnancy is. The goal is always to get the babies to viability at a minimum of 24 weeks gestation if early delivery is required.

How are identical twins delivered?

The majority of twin pregnancies result in cesarean section delivery for the safety of both mother and babies. Vaginal delivery may be possible in some cases where Baby A is head down and certain conditions are met:

  • Pregnancy reached at least 37 weeks gestation
  • Estimated baby weights are appropriate for gestational age
  • No signs of fetal distress
  • No complications like placenta previa or vasa previa
  • No history of previous C-sections

For vaginal delivery of identical twins, Baby A is almost always delivered first. Baby B will likely be in breech position and require maneuvering into optimal position for delivery. An epidural is recommended for pain management. Additional staff will be on standby in the OR in case an emergency C-section is needed.

What special care do identical twins require after birth?

Identical twins often require extra precautions and longer hospitalization after delivery:

  • NICU admission for premature or low birthweight babies to receive supportive medical care.
  • Monitoring blood sugar levels as twin pregnancy increases diabetes risk.
  • Watching for signs of jaundice which is more common in twins.
  • Confirming ability to feed and gain weight adequately before discharge.
  • Checking for any physical anomalies or disabilities requiring early intervention.
  • Educating parents on meeting the higher demands of caring for two newborns.

Expect at least 5-7 days of hospitalization for less complicated twin births. If medical issues arise or extended NICU care is needed, the stay could be several weeks or longer.

Are there ways to prevent complications with identical twins?

Unfortunately, there is very little that can be done to prevent the complications associated specifically with monochorionic monoamniotic twins who share a placenta and sac. However, the following general measures may help reduce risks:

  • Achieving optimal health and fitness before pregnancy.
  • Taking a prenatal vitamin with folic acid prior to conception.
  • Eating a balanced diet and gaining appropriate weight during pregnancy.
  • Avoiding smoking, alcohol, and recreational drugs.
  • Screening for and treating any infections prior to pregnancy.
  • Working with medical specialists and following recommendations.
  • Seeking care immediately for any concerning symptoms.
  • Delivering at a hospital equipped to handle high-risk births.

While some complications are out of a mother’s control, the best thing she can do is try to be as healthy as possible and comply with medical care to achieve the best outcome.

What factors increase the risk with identical twins?

Certain factors can make the risks associated with identical twins even greater:

  • Mother’s age over 30
  • Pre-existing health problems like diabetes, hypertension, clotting disorders
  • History of previous preterm birth or complicated pregnancy
  • Pregnancy achieved through fertility treatments
  • Carrying triplets or higher order multiples
  • Developing problems like preeclampsia or IUGR during pregnancy
  • Monochorionic monoamniotic twins who share everything

The more high-risk factors present, the more vigilant monitoring and preventative care is required. Consulting a specialist is recommended in these cases.

Are there any long term impacts on identical twins?

Research shows that twins face higher rates of certain long term health and developmental impacts including:

  • Increased risk of cerebral palsy
  • Higher rates of autism
  • Greater chance of respiratory complications like asthma
  • Higher rates of ADHD
  • Increased risk of vision and hearing problems
  • More dental complications like crowded teeth
  • Potential for developmental delays requiring early intervention
  • Higher rates of diabetes and cardiovascular disease later in life

Not all twins suffer long term consequences, but their start to life with lower birthweight and other complications appears to impart lasting effects. Supportive medical care and watchful parenting can help minimize risks.


Identical twin pregnancy comes with a number of risks not present for singleton pregnancies or even fraternal twins. TTTS, sIUGR, preterm delivery, placental problems and growth discordance all pose threats. However, with careful monitoring, appropriate interventions when needed, and an experienced medical team, many complications can be managed or avoided. While higher risk, many identical twin pregnancies still result in healthy outcomes, especially with proactive care. Mothers should follow medical advice, watch for concerning symptoms, and deliver at a specialized center for the best results.

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